https://approximated.app

It makes connecting user domains to your app easy and reliable at any scale. Each Approximated user gets the own globally distributed, managed cluster of servers with its own dedicated IPv4 address. Includes (unlimited) edge rule features, DDoS protection, webhooks, and more. Make a simple API call, tell the user to point an A record at the IP, and it’s connected to your app with its own SSL certificates.

Built/building with elixir and phoenix, which has been fantastic.